Logging device for radio tuning instruments



W E. H. LARSON -OGGING DEVICE FOR RADIO TUNING INSTRUMENTS Filed May 4, 1925 INVENTOB EjiLfi/eso/v ATTORNEYS Patented May 31, 1G2? warren stares raraar caries" ERIC H. LARSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE LOGO-DIAL CORI PORATION,

A CORPORATION OF ILLINOIS. J

LOGGING DEVICE FOR RADIO TUNING INSTRUMENTS.

Application filed May 4, 1925. Serial No. 27,986.

My invention relates to improvements in logging devlces for radio tuning 1nstru-- nary radio circuit, and which takes the place 7 of the dial ordinarily disposed upon the rotor shaft, and used for the purpose-of turning the shaft totune the instrument so as to tune in and select certain stations broadcasting.- The device includes means for indicating just what station the instrument is set for, and provides a tape upon which inscriptions pertaining to the station may be inscribed, which inscriptions will be visible only at the time thedevice is actuated to turn the rotor shaft in the position for turning in at that particular station.

A further object of my invention is to provide a device of the type described in which the movement of the tape upon which the call letters pertaining to the stations desired have been logged is moved at arelatively high rate of speed, while the movement of the rotor shaft is relatively slow,

thereby rendering great selectivity in tuning.

A further object of the vinvention is to provide a device of the type described in which the speed of rotation of the control knob is relatively faster than the speed of the rotor shaft, thereby rendering-great ac;

curacy in selecting the stations through rotation of the ,rotor shaft and consequently rotation of the tape A further object of the invention is to provide a device of the character described in which means is employed for maintaining the tape' taut at all times so that there is no possibility of the tape shifting upon its reels or hecomingslack and thus binding within the casing.

A further object of the invention is to provide. a device of the type described in which auxiliary means associated directly with the rotor shaft is employed for indicating the degrees from a predetermined position that the rotor shaft is rotated, which in the'ordinary type of radio circuit is limited to 180.

along the line 4-4 of Figure 3.

A further object of the invention is to provide a logging device for radio tuning instruments which is simple in construction.

Other objects and advantages will appear in the following specification, and the novel features of theiinvention will be particularly pointed out in the appended claims;

My invention is illustrated in the accompanying drawings forming part of this application, in which Figure 1 is a front elevation of an embodiment of the invention,

Figure -2 is a top plan view of. the mechanism illustrated in Figure 1,

' Figure 3 is a sectional view along the line 3-3 of Figure 2 with portions of the interior mechanism broken away, and

Figure lis a sectional view substantially In carrying out my invention I make use of the ordinary type of radio tuning instrument, such as a variable condenser, the external housing of which is shown in Figure 4 at 1. This condenser has arotor shaft '2 which when turned moves certain instru mentalities within the chamber, thereby changing the capacity of the instrument and altering the internal wave length of the radio set of which the condenser or other instrument forms a part. The only portion of these tuning instruments which is important in so far as my present invention is concerned is the shaft A My improved logging device consists in a metal casing 3 having a flat top wall 4 with a rectangular aperture 5 therethrough. The casing 1 has a gear 6' rotatably mounted therein which is provided "with a hollow shaft 7; The rotor shaft 2 is rojected within the hollow shaft and keyed against movement thereto by means of a set screw 8 projected through a portion 9 of the shaft 7 which extends exteriorly of the casin An indicating hand 10 extends radially rom the portion 9 of the shaft 7 and an arcuate scale 11 of 180 is disposed upon the frontv face of the casing 3 in registration with the,

3. A gear 22 is carried by the shaft 13 beneath the aperture.

cause slow rotation of the gear 24.

A pinion 14: is carried by the shaft of the gear 24 which pinion is 111 mesh with the.

gear 6. Thus'rotation of the knob 12 will cause relativelyslow rotation of the shaft 2 in the same direction.

A pair of hollow drums 15 and 16 are rotatably mounted by means of shafts 17 and 18 respectively within the casing 3. The drum 15 has a coiled spring 19; therein. This spring is secured at its innermost end'to the adjacent shaft 17 and at its outermost end to the inner wall of the drum 15' so as to resist rotation of the drum in one direction and thereby tend to rotate the drum 15 in one direction when'the spring is partially wound. A paper tape 20 is secured at opposite ends to the drums 15 and 16 respectively, and is wound upon the peripheral wall of the drums. This tape 20 is passed over a shoe 21 5 in the top wall 1 of the casing.

-When one-half of the tape 20 is wound upon the drum 16, and the other half on the drum 15, the spring 19 is wound up substantially one-half of its capacity.

The gear wheel 2 1 is in mesh with a pinion 25 carried by the shaft 17 associated with the drum 16. A gear 26 is in mesh with the pinion 25 and in mesh with a pinion 27 carried by the ,shaft- 18 associated with the drum 15. Thus rotation of the shaft 13 as by actuation of the lmob 12 will cause the 'drums 15 and 16 to rotate in the same-direction at a higher speed than the shaft 13 and thus move the tape 20 over the shoe 21. The spring 19 serves to take up any slack which might otherwise occur between the drums, due to the constantly changing effective diameter of the drums and tape.

From the foregoing description of the va-' rious parts of the device'the operation there: of may be readily understood. Let us assume that the rotor shaft 2 of the tuning instrument 1 is set so as to tune the radio receiver of which the instrument 1 is a part for receiving radio broadcasting signals from station WMAQ. The operator would then write the call letters of the station VVMAQ, .on the tape 20 as it appears directly in the center. of the aperture.

This station is then logged and the operdtor may at any time turn the knob.

12 so. as to cause the rotor shaft 2 to rotate and. the

tape 20 to move simultaneously to the position necessary to tune in station WMAQ.

' since movement of the tape 20 an'lthe rotor shaft 2 is synchronized by virtue of the pOsitive' gear trains described. The legends WMAQ, will always appear at the center of theaperture 5 when the shaft 2 is in the position to tune in WMAQ.

shaft 2 will set'the Loaoeoe 6 f Let us assume now that it is desired 'to tune in another station which has a, wave relatively close to the wave of the station WMAQ. Station KDKA may be such a station. Thus a slight movement of the rotor instrument 1 for that station when the knob 12 is actuated to' rotate the shaft 2 a slight degree. The tape 20,

however, will travel relatively faster than the rotative movement of the shaft 2,'i. e., theshafts 17 and 18 of the drums 15 and 16 respectively will rotate faster than the shaft 7 which is. connected with the rotor shaft 2.

This will keep another portion of the'tape 20 in registration with the central part of the aperture 5 and the legends KDKA may be marked upon the tape so that the operator at anytime may reset the instrument 1 for that station.

One of the most important features of my invention consists in the mechanism for moving the tape 20 at a relatively high speed relative to the rotation of the shaft- 2. so that there is ample room of legends upon the tape. Accurate tuning of the stations-is made possible by the refor the disposition duced speed between the knob 12 and the ed within said casing, a tape having its op posite ends secured to said drums and bein; wound upon said drums. whereb rotation of said drums in the same direction will cause the tape to pass from one druni to the other, said casing having an aperture therethrongh through which the tape may he obrervcd. a

spring for resisting rotation of said drums 1n one direction. and gears connectingsaid drums with the shaft of said manually actuated pinion, whereby the operation of said manually actuated pinion will cause the rotation of said of speed.

2. The combination with a rotatable control shaft, of a casing having an aperture "therethrough,a'movable tape (lispose'l within the casing and arranged for movement. with respect to said aperture. a control knob, means for turning said shaft when said control knob is turned at a speed less than the control knob. and other means operatively connected with said c ntrol knob for moving said tapeat a re atively greater speed than the rim speed of said control knob.

ERIC H. LARSON. 

